Rotary veneer clipper



1957 E. w. KNOKEY ROTARY VENEER CLIPPER.

2 Sheets-Sheet 1 Filed Oct. 6, 1954 INVENTOR.

Er win WKnokey BY r/ I Oct. 8, 1957 E. w. KNOKEY ROTARY VENEER. CLIPPER2 Sheets-Sheet 2 Filed Oct. 6. 1954 INVENTOR. Er Win WKnokey ROTARYVENEER CLIPPER Erwin W. Knokey, Netarts, Oreg., assignor of one-half toDiamond Lumber Company, Portland, Greg, a corporation of OregonApplication October 6, 1954, Serial No. 460,719

1 Claim. (Cl. 164-48) This invention relates to a veneer clipper such asis employed within the plywood industry to clip or cut a continuoussheet of veneer into pieces of preselected size. More particularly, theinstant invention concerns an improvement in rotary or circular motionveneer clippers whereby the continuous sheet of veneer is sliced or issevered by what is substantially a side to side motion in contrast withthe better known reciprocating or sheartype severance.

One object of my invention is to provide a true rotarytype motion veneerclipper which is capable of operation at speeds heretofore unattainablein the industry in order that the continuous sheet of veneer can be madeto travel at a continuous high rate of speed, without stopping, whilethe clipping progresses, all without damage to or crushing of thefragile and somewhat flimsy veneer sheet.

The production of plywood is a major industry in the Pacific Northwest,which region leads all others in logging operations and in timberresources. The typical plywood board is fabricated from a number of thinlayers of veneer which are glued together so the grain of each layer isat right angles to that of the adjacent or abutting layer. Eachindividual ply or sheet of veneer is the end product resulting from along and complex procedure. At the plywood mill, this process beginswhen a log is snaked from the pond, trimmed to length, and the barkremoved. Thereafter, the log is fed to a huge veneer lathe where acontinuous strip of veneer, usually one-eighth inch thick, is peeledfrom its revolving periphery. This sheet is cut to lengths commensuratewith temporary storage facilities (for example, 1000 foot lengths) andis fed, on belts or conveyors, to horizontal storage racks. Thesestorage racks terminate adjacent the feed belt of the veneer clipperwhere the elongate continuous sheets are cut to smaller sizes correlatedto the dimensions desired in the finished plywood board. At theoff-bearing side of the clipper, the pieces of veneer are stackedselectively, according to the cut, predetermined lengths, and aretransported to a kiln for drying. The cured pieces then are ready forthe final trim and for assembly into plywood boards. It is the veneerclipper per se with which my invention is con cerned.

A typical veneer clipper consists of correlated feed and oif-bearingbelts, respectively, which feed the continuous sheet to and convey thecut pieces from a clipper blade assembly. In general, clipper blades maybe classified in accordance with the type of motion described by theknife during a cutting operation. For example, a majority of priorclipper blades describe a reciprocating, up and down type motionwherein, sequentially (l) the blade makes a rapid operating down strokecut through the continuous sheet; (2) the motion of the blade is stoppedand is reversed; and (3) the blade describes a rapid return stroke toits original position. A second type of clipper operates with pluralknives which rotate and move with the veneer, the axis of rotation beinghorizontal and extending across the table normal to the direction oftravel. A third type of clipper blade is swung on links or otherwise ismounted nited States Patent O 2,808,883 Patented Oct. 1957 for a rotarymotion toward and away from the veneer with the cutting edge of a singleknife maintained parallel to the flat sheet of veneer. This latter typeof motion causes the single knife to swing through an arc, the sheet ofveneer being sliced adjacent the lower terminus of this arc-likemovement. The first and second types of veneer clippers are describedand illustrated in a large number of patents to be found in thereciprocating and rotating motion cutting machine art, and the thirdtype of clipper, somewhat more scarce than either of the first twotypes, is typified by my previous invention, Serial No. 775,654,

filed September 23, 1947, which invention was dedicated to the publicthrough publication in the Oflicial Gazette of the United States PatentOfiice issued September 13, 1949.

Rotary motion, single blade veneer clippers have been developed becauseof the greater speed, larger production volume, and increased accuracywhich is possible therewith. For example, it will be apparent that areciprocating clipper blade must describe a motion which can besummarized as descend, stop, reverse, and return. This type of anoperating cycle is limited in speed of accomplishment by the requirementthat the motion of the blade be stopped and reversed midway of thecycle. With a single knife, rotary type motion, on the other hand, theblade is not stopped midway of the cycle butrather is caused to travelcontinuously. At the same time, of course, the rotary-type motionproduces a slicing rather than a clipping or crushing type cut. Theslicing type cut long has been recognized in the industry as apreferable, cleaner severance.

As those skilled in the art will appreciate, the greater speed possiblewith a rotary-type clipper is one factor which has made practical theelimination of stop and g0 veneer travel. Thus, the industry in recentyears has witnessed a conversion from the former stop and go motion ofthe veneer sheet itself to a continuous feed or motion while the sheetis cut. That is to say, some older clippers stopped the forward motionof the continuous sheet of veneer during the instant that the cut wasmade. This stop was considered essential with the slower reciprocatingtype of clippers, since the veneer itself is flimsy, weak, fragile, andvery thin. When a cut is effected, a moving sheet would be pushedagainst the knife and thus would tend to curl, warp, buckle, or crushthe wood fibers.

As the operating speed of the veneer clipper has increased in recentyears, this requirement for stopping the moving sheet while a cut iseffected has been overcome by various mechanisms. For example, someclippers provide a physical hump or rise immediately before the knifeblade whereby the contact of the moving sheet with the edge of the bladewill cause the following section of veneer to hump up or bend for theinstant that the knife is passing through the sheet to effect a cut. Atbest, this is a half way etficient measure, however, since broken spacesand checks often are enlarged as the sheet is bent. It thus has been thegeneral purpose or goal of the industry in recent years to produce aveneer clipper which will operate with suflicient speed that the knifewill move out of the way without crushing or injuring the flimsy andsomewhat fragile moving sheet. The instant invention provides a clipperwhich, to the best of my knowledge, effects the fastest cutting orslicing cycle yet achieved in the industry, and it is the mechanismwhich achieves this result which forms the subject matter of the instantinvention.

To the above ends, my veneer clipper provides a cut-oif plate and asingle horizontally arranged knife blade which are mounted on pluraleccentric crank arms. These crank arms generate a swinging or a rotarycircular motion of the knife toward and away from the veneer sheetthrough substantially a full circle while maintaining the cutting edgeof the knife parallel with the moving veneer at all' times. The actualslicing motion is effected during the traversal of the lower segmentonly of the circular motion in order that the elements of the clipperassembly can achieve full moving velocity prior to the instant that theveneer is contacted by the knife edge. The veneer thus can be moved at aconstant velocity even while the knife passes through the sheet withoutdanger of injury to the wood fibers or buckling of the veneer.

Referring once more to my previous: invention made available to thepublic through publication in the Ofiicial Gazette, that veneer clipperalso was of the single knife rotary type. As therein described,'theelongated knife bar was carried by plural pivotal links which movedthrough half circles, the opposite ends of the links carrying acounterweight bar of the identical mass and similar shape as the veneerblade and clipper bar. Thus, by moving the pivoted links, thecounterweight bar described a half circle rotary motion in one directionat the same time as the clipper blade and cutoff bar described a halfcircle rotary motion in the opposite direction. During its day, thisassembly was one of the fastest in the industry. It was not, however,without certain inherent disadvantages, one important object of theinstant invention being to provide a single knife rotary-type clipperassembly which overcomes these disadvantages while, at the same time,providing an assembly which is even faster and which produces a cleaner,sharper slicing motion.

In appreciation of the improvements afforded by the instant invention,it is necessary to recognize that the distance between the anvil orcutoff plate over which the veneer travels and the lower edge of theknife is known in the art as the throat or clearance of a clipper bladeassembly. This throat or clearance dimension has, through experience,become fixed in the industry at approximately three inches. Thus, insubstantially all veneer clippers, the knife edge travels three inchesdown and three inches up while describing an operating cycle. With mypreviously mentioned dedicated invention, the link-type mechanism thuswas fabricated with a six inch length which was pivoted at its center toprovide a three inch arm on each side of the pivot. With the link in asubstantially horizontal position, the stroke or clearance thus Wasthree inches. During an actuating cycle, of

course, the link was rotated about the pivot through a half circle(substantially 180 degrees) thereby moving the clipper blade through therequired three inch down and up throat or clearance distance. At thesame time, it will be evident that the three inch vertical componentmovement of necessity was combined with a six inch horizontal componentsince each given point on the knife edge traveled through a half circlethe radius of which was three inches and the diameter of which was sixinches. The actual severance of the sheet of veneer thus was effectedwith an amplified or exaggerated side to side clipping motion at thelower extremity of the operating cycle.

The above described requirement for substantially twice the horizontalcomponent of travel as compared to the vertical component of travel of arotary-type knife now has come to be recognized as a disadvantage orlimitation. As will be appreciated by those skilled in the art, thehardness and the strength of the veneer varies with the species of wood.Thus, with certain species of wood, the veneer sheet is flimsy, weak,and somewhat yielding in texture. With the above described link or halfcircle motion clipper blade, the extreme component of side to sidemotion sometimes exhibited a tendency to chop, to slide, or to move thesheet of veneer sideways during the cutting of the blade through theveneer. It thus is one object of the instant invention to provide amechanism which will limit the lateral or sidewise component of theblade movement consistent with the requirement for a normal throat orclearance in order to eliminate this tendency to chop, slide, or movethe sheet *4 of veneer sidewise when the veneer is a species of wood noteasily cut.

Another object of my invention is to provide a rotarytype veneer clipperwherein the motion of the clipper blade describes substantially a fullcircle, in contrast with a half circle, in order that the throat orclearance of the blade will allow an increased vertical component ofmotion or travel before the knife actually contacts the wood. In sumtotal, this provision allows the clipper assembly to be operated at ahigher rate of speed and, during each cycle of operation, to achieve amaximum velocity before the moment of actual contact of the blade withthe traveling sheet of veneer so as to effect a clean severance.

Another object of my invention is to provide a rotarytype veneer clipperwherein the use of 'counterweights is eliminated and the overall mass ofthe clipper blade is held to a minimum so as to produce a minimuminertia of the moving parts and thus to allow the assembly to accelerateand to move faster.

In accordance with the last described inventive object, it will berecognized that the moment of inertia of a body is a function and isdirectly related to the mass of that body. Furthermore, inertia is thatproperty of a body by virtue of which the body tends to continue in astate of rest or motion in which it may be placed until acted upon bysome external force. A veneer clipper assembly, including all movingparts and counterweights, if any, can be considered to be such a bodyfor purposes of examination and evaluation. By eliminating the use of acounterweight in the instant assembly, I have reduced the inertia to aminimum and, accordingly, have minimized the resistance to movement orto change of direction of the clipper 'blade assembly. This minimalinertia construction allows the clipper blade to come up to fulloperating velocity and to achieve a higher maximum velocity with thesame application of power. Further, since the motion of the moving bladeis in a circle rather than in a straight line, down and up, the motionis more or less continuous and uninterrupted. This allows a highervelocity.

Yet another object of my invention is to provide a rotary motion typeveneer clipper wherein the conveyor for moving the sheet of veneer isreeved about pulleys which are located on the off-bearing sides of theclipper blade assembly in order to minimize the collection of trash anddebris on these pulleys during the operation of the clipper blade. Theneed for this provision is emphasized by the higher operating speed ofthe blade assembly of the instant invention and by the necessity for asmooth, uninterrupted movement of the sheet of veneer if full advantageis to be taken of this blade speed.

These and other objects and advantages of my invention will be describedwith reference to the accompanying drawings, wherein:

Fig. 1 is a back elevation or what is termed in the indnstry an outfeedview showing the complete veneer clipper and conveyor system, togetherwith the twin air motor actuation cylinders therefor;

Fig. 2 is an enlarged and somewhat diagrammatic view of the knife edgein motion as it slices through a sheet of veneer, the rotary motion ofthe cutoff plate, knife and gears being indicated diagrammatically bydirection arrows in order to illustrate the function of the mechanism;and

Fig. 3 is a section detail, taken substantially on the line 33 of Fig.1, showing the cutoff plate, gib plate, and the crank arm means wherebythe rotary motion of a spur gear is transferred to an eccentricrotary-type motion of the knife blade, this figure further illustratingthe location of the feed belt conveyor pulley on the offbearing side ofthe clipper assembly whereby trash and debris generated by the operationof the clipper blade is inhibited from accumulating on the pulley andthus slowing or limiting efiective operation of the high speed conveyorsystem. 7 r

In general orientation, the veneer clipper of Fig. l is located in aplywood mill intermediate the lathe which peels the continuous strip ofveneer from the revolving periphery of a log and the sorting table fromwhich pieces of green veneer are stacked selectively according topredetermined lengths cut by the clipper. In-this figure, the pluralfeed belts are indicated at and the off bearing belts at 6. These beltsare rotated by a common drive shaft 7 through appropriate pulleys suchas illustrated at 8 in Fig. 3. As indicated in this figure, the driveand the idler pulleys (not shown) are located on opposite sides of andare spaced from the clipper blade assembly generally identified at K. Itis the function of the feed belts 5 to deliver the continuous sheet ofveneer to the clipper blade assembly and of the offbearing belts 6 toremove the clipped or cut pieces of veneer to an end point of use.Appropriate motor drive mechanism to elfect this function may beprovided by an electric motor or the like, as will be appreciated bythose skilled in the veneer clipper art.

The conveyor system above described lies substantially in the same planeas the surface of the top of a table 9 and thus functions to move asheet of veneer over what can be seen to be a substantially horizontaltable top. In conjunction therewith, the main structural elements of theclipper blade assembly consist of the frame members indicated in generalat F in Figs. 1 and 3. These frame members stand up on the floor of theplywood mill in order efliciently to hold and to position the operatingand moving elements of the clipper blade assembly.

Adjacent the top of Fig. l, I have illustrated a pair of air motors orpiston and cylinder units 10. These motors are mounted end to end withthe respective piston rods 11 thereof aligned and pivotally joined, asat- 12, to a pair of spur type gear actuation means 13. An appropriatemotor control valve is provided at 14 'to regulate the supply andexhaust of air pressure via the four hoses 15 to the two air motors 10.A supply tank 16 and exhaust line' 17 connect with the valve 14 and thehoses 15, air flowing thereto and therefrom as indicated by the arrowsin Fig. 1. Thus, an appropriate actuation of the valve 14 will supplyair simultaneously to the right end of both motors 10 while exhaustingthe air from the opposite ends thereof. An opposite manipulation of thevalve 14 will supply air to the left end of both motors 10 whileexhausting air from the right ends thereof. Since the piston rods 11define pitrnans, these various actuations of the air motor 10 willrotate the two large spur type gear actuation means 13 in eitherdirection selectively. That is to say, both of these gears 13 rotateeither counterclockwise or clockwise at the same time in accord with themovements of the motors 10.

In order to accommodate the limited pivotal movement of each air motor10 during an actuating cycle, pivotalmounting therefore is provided at18. Additionally, it will be noted that one of the piston rods 11 is intension while the other is in compression during each operating cycle ofthe clipper blade assembly. This factor provides a more balancedconstruction and tends to eliminate 'slackness or sloppiness in thefitting of the vafious parts. 7

Referring now to Fig. 3, it will be noted that each of the large spurtype actuation means 13 is journaled, as at 19, and is meshed with apair of smaller spur gears 20. Thus, each of the large gears 13 is adriver which rotates -a pair of the smaller spur gears 20. In thismanner, rotary motion is translated to four of the small spur gears 20simultaneously during actuation of the clipper blade assembly.

Referring now to Fig. 3, each of the small spur gears 20 is keyed to ahorizontal drive shaft 21, the ends of which are carried in rollerbearings 22. The shaft 21,

in turn, terminates in a circular plate 23 having integral therewith'ashort horizontal driven arm 24. As can be seen in Fig. 3, the short arm24 is off center or eccentric with respect to the axis of rotation ofthe drive shaft 21- and, together with the plate 23, thereby defines aneccentric crank arm means.

In joinder of the short driven arm 24 and the knife blade K, the clipperblade assembly includes an elongated cutoff plate 25. The knife Kdetachably is joined thereto, as by bolts 26, and the arm 24 is carriedin roller bearings 27. Retention of these latter bearings is effected bymeans of a housing 28 and cover 29, both of which detachably are securedas by bolts 30 and 31. Thus, the end. ofthe crank arm 24 effectively is'journaled in bearings 27 which are carried within an aperture formed inthe cutoff plate 25. By utilizing this type of anassembly, I am enabledto remove the bearing assembly 27 quickly and without disturbing theremainder of the clipper assembly merely by removing the cover plate 29and the nut which is threaded upon the end of the arm 24. It will beappreciated that considerable force is transmitted in rotationby thisbearing assembly 27 and thatthis force will become evident by wear.Accordingly, this provision for removal and replacement of the entirebearing is of importance to the practical continued operation of theclipper blade assembly.

During an operating cycle of the cutoff plate 25 and knife K, a bearingsurface and guide is provided by a vertically disposed gib plate 32.This gib plate provides a plane smooth surface against which thecorresponding plane smooth surface of the cutoff plate 25 will rub andbear. The sliding contact thereby provided restrains the cutoff plate tomovement in a plane which, as shown in Fig. 3, is vertical.Additionally, looseness in the parts can be taken up by anadjustnientwhich will move the gib 32 slightly to the left as viewed inFig. 3. This adjustment is effected by means of a plurality of threadedlock and bolt assemblies 33. The bolt of each of these assemblies bearsupon the top of the gib and is received in threads tapped into theaforementioned frame F. Additionally, the gib 32 is formed with anoblique or sloping back face, as can be seen in dashed outline in Fig.3. Movement of the gib to the left is effected by tightening the boltassemblies 33 to move the gib downwardly upon the sloping back face.Thus, the cutoff plate 25 and knife K will retain their verticaldisposition yet Will be moved or adjusted slightly to the left withrespect to the frame F and associated mechanism. In actual practice, anadjustment of the bolts 33 is effected only when some wear of the partshas made the assembly loose or sloppy in fit.

Returning now to Fig. 1, it will be noted that the crank arm means 20,21, 23, 24 are eight in number whereas only four of these are drivenbythe large spur gear drivers 13. The remainder of these crank arms arenonpowered guides which serve merely to retain the knife K in a parallelor horizontal relationship with respect to the table 9 during operation.Thus, those crank arms which are idlers (not driven) are identical instructure to the crank arm shown in Fig. 3, except that no large drivegear 13 or small driven spur gear 20 is provided. Instead the structureconsists merely of a shaft such as 21, roller bearings 22, a plate 23,an arm 24, and the associated bearing structure 27. In a high speedclipper such as here illustrated, this multiple guide arrangementreduces vibration and produces a smoother operating structure.

' Operation Referring to Figs. 2 and 3, it will be noted that the knifeK moves slidably across the edge of an anvil A while elfecting a cuttingoperation. This anvil could as well be a cutoff bar since both arecommon in the industry. In these figures, the total vertical componentof travel of the knife blade is indicated by the reference letter T.This letter T indicates the dimension of the throat or clearance of theknife above the anvil A and, in a majority of veneer clipper assemblies,the dimension is approximately three inches. Additionally, the movementof the knife K and cutoff plate 25 is shown by direction arrows. As isshown in Fig. 3, the belts and 6 lie in tunnels recessed in table top 9so that the upper surfaces of said belts lie in the same plane as thatof said table top. Said belts underlie the anvil A, and thus the knife Kcan pass substantially below the upper face of the anvil A withoutstriking the table top or cutting said belts. The peripheral outline ofthe large spur type actuation gear 13 is shown by a dashed linerepresentation in Fig. 2 as it meshes with the two adjoining smallerspur gears 20. Thus, a rotation of the large spur gear 13 will rotateboth of these smaller spur gears 20 simultaneously in order to move theknife K through a rotary or a circular type operating cycle.

In assembling my rotary veneer clipper, I prefer to pro-portion thevarious gear teeth and the driving and driven rods and crank arms suchthat a single stroke of the air motors will move the small spur gears 20through substantially a full circle.

As shown in Fig. 2, this movement is approximately 345 degrees, althoughit could as well be a full circle of 360 degrees. Thus, I use the termsubstantial to indicate a movement which is within 15 or degrees of ageometric full circle.

Adjacent the bottom of Fig. 2, direction arrows 34 have been used toindicate the rotary movement traced by a given point on the knife K.Thus, as the air motors 10 move through a full stroke from one extremityto the other, a given point on the knife edge K will move in a circularpattern as traced by the arrows 34. In this connection, itwill be notedthat the tangent to the lower limit of the circular motion described bythe cutting edge of the knife lies immediately below the sheet of veneerand below the anvil A. This tangent to the lower limit of the circularmotion is horizontal and is illustrative of the fact that the sheet ofveneer is cut with a rotary slicing motion during the sidewise traversalof the lower segment only of the circle 34. Additionally, Fig. 2demonstrates that each rotary operating motion of the cutoff plate andknife both begins and ends with the cutting edge of the knife K spacedabove the table top 9 and above the veneer a distance which issubstantially equal to the diameter of the circle 34. It is thisdiameter which is identified by the throat T and is substantiallyequivalent to the diameter of the circle 34.

Various types of manual, automatic or semiautomatic controls can beprovided for my veneer clipper, these controls forming no part of theinstant invention. Suflice to say, these controls serve to effect anactuation of the air motor control valve 14. For example, one operatingcycle is initiated by manipulation of the valve 14 in ordersimultaneously to feed air pressure to the left side of both motors 10while exhausting pressure from the right sides thereof. The air motors10 then move the two piston rods or pitmans 11 toward the right in Fig.1 causing the large spur gears 13 to rotate in a clockwise direction.This clockwise rotation is transferred to a counterclockwise rotation ofthe eight driven and idler small gears 20. In Fig. 2, this is theparticular operating cycle described by the direction arrows 34 and bythe direction arrows associated with the two small gears 20.

During an operating cycle, the knife blade itself also describes arotary motion as illustrated by the arrows 34. Because it is only theextreme lower segment of this circular motion during which the knife Kactually is cutting through the veneer, the entire blade assembly isenabled to come up to full velocity'before it contacts the upper surfaceof the sheet of veneer. Additionally, it will be noted that the bladeassembly and knife movement is one of continuous motion from the instantthat the valve 14 first is manipulated until the knife edge K hastraversed a complete circular cycle. This absence of a stop in motion,which stop was conventional with reciprocating type clipper blades,allows the entire mechanism to be operated at a much faster speed thanprior veneer clippers. For example, I have found that the instantclipper can be operated with such rapidity that but one-twelfth of asecond is consumed by each full operating cycle. This speed allows theveneer to continue moving without danger of buckling or crushing of thefragile fibers, and thus is productive of a higher output in the plywoodmill.

In summary, it will be seen that I have provided a single knife rotarytype veneer clipper which is capable of operation at higher speeds thanheretofore has been considered possible. Additionally, the circularmotion described by the knife blade is substantially a full circlewhereby the same throat or clearance required with all clippers isaccommodated yet the total path of travel of the knife is minimized.These factors produce a slicing cut with a minimal sidewise travel andallow the knife assembly to come up to full operating speed prior to theinstant that the sheet of veneer is contacted by the knife edge. Theythus add to the overall operating speed and efficiency of the clipper.Still further, by providing a feed belt pulley which is on theolfbearing side of the knife rather than immediately adjacent the pointof contact of the knife with the anvil, I am enabled to maintain aclean, smooth operating pulley system which is free from accumulateddebris and trash in spite of the high rate of productivity. That is tosay, my pulley system is free of accumulated debris and trash becausethey are located at the offbearing side of anvil A and top 9, and isshown in Fig. 3. The trash and debris produced by the cutting action ofknife K accumulates at the forward or infeed side of said anvil A. Theanvil tends to brush said debris from the upper surface of the clippedveneer and it falls downwardly over the left-hand side of said table top9. It is thus prevented from falling downwardly on the pulley 8, whichis located far to the right of the cutting line of the knife K.

I claim:

In combination with a table having conveyor means for moving a sheet ofveneer thereover, an elongated cutoff plate mounted above but movable ina plane toward and away from said table as guided by a single planeguide face on the plate, said cutofi plate carrying a single knife bladewith a single cutting edge parallel the surface of said table, a gibplate means parallel to and in sliding contact with said plane guideface only thereby to define a single face bearing surface guiding andrestraining said cutoff plate to movement in a plane, means foradjusting said gib plate laterally with regard to said cutoff plate,thereby to maintain the movement of said cutoff plate to movement insaid plane, and plural eccentric crank arm means operatively journaledwithin bearings housed within said cutoif plate to move the cutoff platein rotation through substantially a full circle while maintaining saidcutting edge parallel to the surface of said table, selected ones ofsaid plural eccentric crank arm means including a short horizontaldriven arm which extends through and is journaled within an aperture insaid cutofi plate carrying a corresponding one of said bearings, each.said driven arm being operatively joined to and parallel with .anelongated horizontal driven shaft having an axis of rotation off centerwith respect to the axis of the driven arm, selected others of saidplural eccentric crank arm means being nonpowered guides and eachincluding a short horizontal idler arm which extends through and isjournaled within an aperture in said cutoff plate carrying acorresponding one of said bearings, said nonpowered guides alsoincluding an elongated horizontal idler shaft operatively joined to andparallel with each said idler arm but having an axis of rotation oifcenter with respect to the axis of the corresponding idler arm, a spurgear fixed to each of said selected horizontal drive shafts for rotationtherewith, a pair of spur gear actuation means spaced longitudinally ofsaid cutoff plate with each spur gear actuating means operativelymeshing with a separate pair of said spur gears fixed to said selectedcrank arm means to rotate the same in either direction throughsubstantially a full circle of rotation, and a pair of air motor meansmounted end to end centrally above said cutofi plate with the pistonrods of the motors aligned but extending in opposite directions intopivotal connection with respective ones of said gear actuation means todefine pitmans.

References Cited in the file of this patent UNITED STATES PATENTS 84,306Sanborn Nov. 24, 1868 156,217 Greenman Oct. 27, 1874 1,224,107 Hawkinset a1 Apr. 24, 1917 1,448,404 Hort Mar. 13, 1923 1,467,378 Hanson Sept.11, 1923 Seybold Mar. 10, 1924 Stanley Jan. 19, 1932 Willgoos Aug. 8,1939 Bugatti Sept. 23, 1941 Keagle Mar. 11, 1948 Munschauer July 14,1953 Wikle Feb. 7, 1956 FOREIGN PATENTS Denmark Jan. 21, 1946 OTHERREFERENCES Knokey: Abstract of application Serial Number 775,654,

